The projected need for Indian rhesus macaques for AIDS-related research continues to exceed availability. Given the interest in nonhuman primates for bioterrorism and emerging disease research, this shortage will likely continue for years to come. While source countries are a potentially important reserve of untapped production the increasing difficulty of transporting nonhuman primate both internationally and domestically suggests relying on imports may provide only short term relief. Expanded domestic breeding programs managed to produce well characterized animals that enhance their use in biomedical research offer the best long-term solution for the current shortage of Indian-origin rhesus macaques for AIDS vaccine and pathogenesis studies and to insure future availability. The objective of this application is to continue expanding the capacity and improving on the level of genetic characterization of the specific pathogen-free Indian rhesus AIDS Research Colony resource initiated during the first grant period. The specific aim for accomplishing this objective is to intensively managing the new AIDS Research colony for maximum production of genetically diverse females to expand the breeding capacity. Selective breeding methods will be used to enhance production of future breeder males that are homozygous for scientifically important alleles. These animals can be used to efficiently produce large numbers of offspring carrying the desired allele without resorting to inbreeding The current level of genetic characterization in the colony will be expanded to include MHC class II loci. The acquisition of additional sheltered field cage housing is proposed to support colony expansion in an environment that protects these valuable animals from infectious agents in the environment.